The answer is : Limestone
Trisomy=3 chromosomes; 1 more than the required pair (2)
21=the type of chromosome
So, here we can eliminate A and B.
Now we have C and D.
I know that when sperm cell(s) simultaneously fertilize [an] egg, a class of identical twins will form. Therefore, we can eliminate D, leaving us with merely C. Henceforth, C is your final answer.
The energy from sunlight comes in the form of photons, and this energy is used in the light dependent reactions of photosynthesis. The first function carried out by the photons in energizing electrons in the chlorophyll. The energized electron travels through the electron transport chain and subsequent steps are carried out to utilize this energy to form ATP.
The answer is "Groundwater"
Bacteria is named based on their basic shapes